Conventionally, in order to prolong the lifetime of LED (light emitting diode) bulbs, it is necessary to efficiently release the heat generated by the LED elements so that the LED elements and the LED control circuit are not damaged by the heat. Therefore, an LED bulb which controls the increase of temperature of the lighting circuit when the LED light is lit and maintains the lifetime of the lighting circuit (refer to patent document 1). As for the LED bulb described in the patent document 1, as shown in the FIG. 1 of the patent document 1, the LED module 11 is added to the heat releasing element 12 and the heat from the LED is released from the plurality of heat releasing fins 18 of the heat releasing element 12. A lighting circuit 17 which lights the LED is embedded in the hallow part 23 of the metal cap 16 which is located on the opposite side of the globe 14 of the heat releasing element 12.
As for the LED bulb described in the patent document 1, it is possible to make the distance between the LED module 11 and the lighting circuit long, and the heat releasing element 12 and the metal cap 16 are insulated by the insulation 15. As such, the heat generated by the LED of the LED module 11 is not conducted to the lighting circuit 17 but mostly released at the heat releasing element 12, thus the temperature increase of the lighting circuit 17 is suppressed.